REVIEW 7 cited by
Evolution of the UV slope of galaxies at cosmic morning (z > 4): the properties of extremely blue galaxies
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Signed reviews
read the original abstract
We present an analysis of the UV continuum slope, beta, using a sample of 733 galaxies selected from a mixture of JWST ERS/GTO/GO observational programs and with z > 4. We consider spectroscopic data obtained with the low resolution PRISM/CLEAR NIRSpec configuration. Studying the correlation of beta with M_UV we find a decreasing trend of beta = (-0.056 +- 0.017) M_UV - (3.01 +- 0.34), consistent with brighter galaxies having redder beta as found in previous works. However, analysing the trend in separate redshift bins, we find that at high redshift the relation becomes much flatter, consistent with a flat slope. Furthermore, we find that beta decreases with redshift with an evolution as beta = (-0.075 +- 0.010) z - (1.496 +- 0.056), consistent with most previous results that show a steepening of the spectra going at higher z. We then select a sample of galaxies with extremely blue slopes (beta < -2.6): such slopes are steeper than what is predicted by stellar evolution models, even for dust free, young, metal poor populations, when the contribution of nebular emission is included. We select 51 extremely blue galaxies (XBGs) and we investigate the possible physical origin of their steep slopes, comparing them to a sub-sample of redder galaxies (matched in redshift and M_UV). We find that XBGs have younger stellar populations, stronger ionization fields, lower dust attenuation, and lower but not pristine metallicity (~ 10% solar) compared to red galaxies. However, these properties alone cannot explain the extreme beta values. By using indirect inference of Lyman continuum escape, using the most recent models, we estimate escape fractions f_esc > 10% in at least 25% of XBGs, while all the red sources have smaller f_esc. A reduced nebular continuum contribution as due to either a high escape fraction or to a bursty star-formation history is likely the origin of the extremely blue slopes.
Forward citations
Cited by 7 Pith papers
-
Clump-Scale Dust Attenuation in Epoch of Reionization Galaxies: Spatially Resolved Properties from FirstLight Simulations
In FirstLight EoR galaxies, star-forming clumps show grayer dust attenuation curves and ~10× higher dust column densities than the system-integrated average, while diffuse regions have steeper curves.
-
pySTARBURST99: The Next Generation of STARBURST99
A Python rewrite of STARBURST99 with new low-metallicity and very massive star models predicts a 0.3 dex boost in HI ionising flux when the upper mass limit is raised from 120 to 300 solar masses.
-
Redshift evolution of Lyman continuum escape fraction after JWST
Average Lyman continuum escape fraction rises from 0.007 at z=0 to 0.6 at z=20, driven by radiation-powered outflows in high-sSFR galaxies.
-
Zapped then Napped? A rapidly quenched remnant leaker candidate with a steep spectroscopic $\beta_{UV}$ slope at z=8.5
JADES-GS8-RL-1 is a z=8.5, low-mass galaxy that appears to have formed stars in a short burst and then rapidly quenched, with a steep blue UV slope and a tentative [OII] detection consistent with a high escape fraction.
-
Signatures of Rapidly Rotating Stars with Chemically Homogeneous Evolution in the First Galaxies
Rapidly rotating, chemically homogeneous stars can increase a galaxy's rest-frame UV luminosity by a factor of 3-6 and allow JWST's z~12-16 UV luminosity functions to be matched with less extreme star formation parameters.
-
The ionizing photon production efficiency of star-forming galaxies at $z\sim 4-10$
JWST Balmer-line measurements of 761 galaxies at z=4-10 show that ionizing photon production efficiency rises with redshift and is highest in faint, low-mass, high-sSFR galaxies.
-
A Galaxy with an Extremely Blue UV Slope $\beta=-3$ at $z=9.25$ Identified by JWST Spectroscopy: Evidence for a Weak Nebular Continuum and Efficient Ionizing Photon Escape?
A galaxy at z=9.25 shows an extremely blue UV continuum slope beta=-2.99, which the authors interpret as evidence for an ionizing photon escape fraction above 0.5.
Discussion (0). Continue with ORCID to comment.